<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>伪元素</title>
  <style>
      * {
          margin: 0;
          padding: 0
      }

      li {
          list-style: none;
          margin-left: 10px;
          padding-left: 10px;
          font-size: 20px;
          text-decoration: underline;
      }

      li::before {
          content: ">  ";
          color: red;
      }
      li::after {
          content: "  <";
          color: red;
      }

  /*    伪元素常见应用, 清除浮动 clearfix类名 配合 ::before 和 ::after */
  </style>
</head>
<body>
<ul>
  <li>java</li>
  <li>python</li>
  <li>c++</li>
</ul>
</body>
</html>